Improved colorimetric analysis for subtle changes of powdered anthocyanins extracted from Lycium ruthenicum Murr

Research Progress on Anthocyanin-Mediated Regulation of 'Black' Phenotypes of Plant Organs

The color pattern is one of the most important characteristics of plants. Black stands out among the vibrant colors due to its rare and distinctive nature. While some plant organs appear black, they are, in fact, dark purple. Anthocyanins are the key compounds responsible for the diverse hues in plant organs. Cyanidin plays an important role in the deposition of black pigments in various plant organs, such as flower, leaf, and fruit. A number of structural genes and transcription factors are involved in the metabolism of anthocyanins in black organs. It has been shown that the high expression of R2R3-MYB transcription factors, such as PeMYB7, PeMYB11, and CsMYB90, regulates black pigmentation in plants. This review provides a comprehensive overview of the anthocyanin pathways that are involved in the regulation of black pigments in plant organs, including flower, leaf, and fruit. It is a great starting point for further investigation into the molecular regulation mechanism of plant color and the development of novel cultivars with black plant organs.

Interaction of preheated whey protein isolate with rose anthocyanin extracts in beverage model system: Influence on color stability, astringency and mechanism

Preheating proteins have the potential to improve anthocyanin stability. Our aim was to investigate the effect of preheated whey protein isolate (WPI) on the color stability and astringency of the beverage model system in the presence of rose anthocyanin extracts (RAEs), and to explore the mechanism of interaction between preheated WPI and RAEs. The secondary structure, particle size and transparency of WPI were obviously changed by preheating. WPI preheated at 100°C  (WPI100) could effectively improve the color stability of RAEs in the beverage model system. Importantly, the WPI100-RAEs in the beverage model system exhibited the smallest particle size and the weakest astringency effect. In addition, different preheated WPIs could interact with RAEs non-covalently, and the interaction forces are hydrogen bonding and van der Waals forces, among which WPI100 had the strongest binding ability to RAEs. These results will provide a new insight into the development of protein-anthocyanin beverages.

Chemical Constituents and Molecular Mechanism of the Yellow Phenotype of Yellow Mushroom (Floccularia luteovirens)

(1) Background: Yellow mushroom (Floccularia luteovirens) is a natural resource that is highly nutritional, has a high economic value, and is found in Northwest China. Despite its value, the chemical and molecular mechanisms of yellow phenotype formation are still unclear. (2) Methods: This study uses the combined analysis of transcriptome and metabolome to explain the molecular mechanism of the formation of yellow mushroom. Subcellular localization and transgene overexpression techniques were used to verify the function of the candidate gene. (3) Results: 112 compounds had a higher expression in yellow mushroom; riboflavin was the ninth most-expressed compound. HPLC showed that a key target peak at 23.128 min under visible light at 444 nm was Vb2. All proteins exhibited the closest relationship with Agaricus bisporus var. bisporus H97. One riboflavin transporter, CL911.Contig3_All (FlMCH5), was highly expressed in yellow mushrooms with a different value (log₂ fold change) of −12.98, whereas it was not detected in white mushrooms. FlMCH5 was homologous to the riboflavin transporter MCH5 or MFS transporter in other strains, and the FlMCH5-GFP fusion protein was mainly located in the cell membrane. Overexpression of FlMCH5 in tobacco increased the content of riboflavin in three transgenic plants to 26 μg/g, 26.52 μg/g, and 36.94 μg/g, respectively. (4) Conclusions: In this study, it is clear that riboflavin is the main coloring compound of yellow mushrooms, and FlMCH5 is the key transport regulatory gene that produces the yellow phenotype.